This invention relates to an improved structure for traffic signals that may be suspended over highways or rigidly attached to posts alongside highways.
Traffic signals with the familiar, red, green, and yellow lights for controlling automobile and pedestrain traffic are frequently enclosed in a plastic housing which may be suspended over the roadway from an arm or one or more cables, or attached to a post alongside the roadway. The normal component parts of these signals include a generally rectangular housing in which the lighting fixtures and wiring are contained and protected from the weather, or a rigid wire entrance fixture which is a specially designed metallic pipe elbow though which power lines enter the housing and from which the entire combination may be suspended from an overhead structure or from cables or otherwise supported by posts. The experience of using this combination has been satisfactory except for a tendency for the plastic housing to fail around the connection between the rigid wire entrance fixture and the more flexible housing. A study of the failures has led to the conclusion that the cyclic bending and twisting of the signal housing due to gusts of wind and other atmospheric conditions caused fatigue failure of the plastic around the rigid connection to the wire entrance fixture.
It is an object of this invention to provide an adapter to be employed between the wire entrance fixture and the traffic signal housing to eliminate, to the maximum extent possible, fatigue failure of the type experienced in the past.